Quick-change bearing assembly that obviates the need to recenter replacement spindles

ABSTRACT

The present invention provides an improvement for use in a machine tool having a spindle ( 51 ) mounted in a body opening ( 30 ) for axial and rotative movement relative to a body ( 31 ). The improvement includes a bearing assembly ( 25 ) that permits spindles (S 1 , S 2 , S 3 , . . . ) to be quickly exchanged while obviating the need to recenter a replacement spindle with respect to the opening after the original spindle has been initially center therein. The improved bearing assembly ( 25 ) broadly includes: a ferrous tubular sleeve ( 29 ) mounted in the body opening, the sleeve having an outer surface ( 40 ) arranged to face toward a portion ( 31 ) of the body that surrounds the opening and having an inner surface ( 36, 39 ) arranged to face toward a penetrant portion of the spindle; and a tubular bearing ( 46 ) arranged within the sleeve, the tubular bearing having an outer surface ( 51 ) arranged to face the sleeve inner surface and having an inner surface ( 50 ) arranged to face the spindle penetrant portion.

TECHNICAL FIELD

The present invention relates generally to bearings for mountingspindles on machine tools, and, more particularly, to an improvedquick-change bearing assembly that obviates the need to recenterreplacement spindles.

BACKGROUND ART

In certain machine tools, such as automatic screw machines, a spindle ismounted for rotation relative to a body or head.

When initially mounted on the head, the spindle must be centered withrespect to the head. To do this, shims are traditionally added whereneeded, to center the axis of the spindle with respect to the axis ofthe head or body opening.

However, with prior art arrangements, each time the spindle is removedor replaced, the reinstalled or replacement spindle must be recenteredwith respect to the body opening.

Accordingly, it would be generally desirable to provide a quick-changebearing assembly that will allow spindles to be quickly and easilyremoved, replaced and exchanged, and that will obviate the need torecenter a reinstalled or replacement spindle after the original spindlehas been centered.

DISCLOSURE OF THE INVENTION

With parenthetical reference to the corresponding parts, portions orsurfaces of the disclosed embodiment, merely for purposes ofillustration and not by way of limitation, the present invention broadlyprovides an improved bearing assembly for use in a machine tool having aspindle mounted in a body opening for movement relative to the body.

The improved bearing assembly permits spindles to be quickly exchangedand obviates the need to recenter a replacement spindle (S1, S2, S3, . .. ) with respect to the opening after the original spindle has beeninitially centered therein. As used herein, a replacement spindle is aspindle that is to be installed after a previous spindle has beenremoved. Thus, the replacement spindle may be a reinstallation of thesame spindle that had been removed, or maybe a new spindle.

The improved bearing assembly (25) includes: a tubular sleeve (29) of aferrous metal mounted in the body opening (30), the sleeve having anouter surface (40) arranged to face toward the portion of the body thatsurrounds the opening and having an inner surface (36, 39) arranged toface toward a penetrant portion of a spindle; and a tubular bearing (46)arranged within the sleeve, the tubular bearing having an outer surface(51) arranged to face the sleeve inner surface (36, 39) and having aninner surface (50) arranged to face the spindle penetrant portion.

The tubular bearing inner surface is arranged to slidably engage thespindle penetrant portion.

In the preferred embodiment, the sleeve inner surface (36, 39) iscylindrical, and a portion (40) of the sleeve outer surface isfrusto-conical.

The tubular bearing is preferably formed of bronze.

The spindle is desirably mounted in the body opening for rotational andaxial movement relative to the body.

The improvement may further include: a pin (33) engaging the body andthe tubular sleeve to prevent relative movement therebetween. To thispurpose, the body may be provided with a blind hole (32) to receive onemarginal end portion of the pin, and the tubular -sleeve may be providedwith a blind hole (42) to receive the opposite marginal end portion ofthe pin.

In the preferred form, a groove (59 or 70, 71 or 84) extends into thetubular bearing from the inner surface thereof for distributinglubricant between the spindle and the bearing inner surface. This groovemay extend into the bearing in a longitudinal direction (e.g., 71), aradial direction (e.g., 70), or the like. In one form, the groove (84)extends helically into the bearing.

The sleeve outer surface may have an portion (41) that is externallythreaded, and the improvement may include a nut (92) arranged tomatingly engage this sleeve externally-threaded portion

The improvement may further include: a interlock mechanism (72, 73 or93) acting between the sleeve and bearing to prevent relative movementtherebetween in one direction. In one form, this interlock mechanismincludes a tapped hole (61) arranged in one of the sleeve and bearing,and a headed fastener (62) threaded into the tapped hole and having ahead portion engaging the other of the sleeve and bearing. In anotherform, the interlock mechanism includes an annular groove extending intoone of the sleeve and bearing, and a retaining ring (93) having oneportion received in the annular groove and having another portionengaging the other of the sleeve and bearing.

Accordingly, the invention broadly provides an improved bearing assemblythat allows spindles to be quickly exchanged while obviating the need torecenter a replacement spindle after the original spindle has beeninitially centered therein.

Another object is to provide an improved bearing assembly that allowsspindles of different shapes and configurations to be quickly and easilyreplaced and exchanged.

These and other objects and advantages will be come apparent from theforegoing and ongoing written specification, the drawings and theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary longitudinal vertical sectional view of a firstform of the improved bearing assembly in association with a firstspindle.

FIG. 2 is a fragmentary longitudinal vertical sectional view of thebearing assembly shown in FIG. 1, with the first spindle removed.

FIG. 3 is a fragmentary longitudinal vertical sectional view of a secondform of the improved bearing assembly in association with a secondspindle.

FIG. 4 is a fragmentary longitudinal vertical sectional view of thebearing assembly shown in FIG. 3, with the second spindle removed.

FIG. 5 is a fragmentary longitudinal vertical sectional view of a thirdform of the improved bearing assembly in association with a thirdspindle.

FIG. 6 is a fragmentary longitudinal vertical sectional view of thebearing assembly shown in FIG. 5, with the third spindle removed.

FIG. 7 is a left end elevation of the ferrous tubular sleeve.

FIG. 8 is a fragmentary longitudinal vertical sectional view thereof,taken generally on line 8-8 of FIG. 7.

FIG. 9 is a top plan view of the ferrous tubular sleeve shown in FIGS. 7and 8.

FIG. 10 is a left end elevation of a first form of the tubular bearingshown in FIG. 1.

FIG. 11 is a fragmentary longitudinal vertical sectional view thereof,taken generally on line 11-11 of FIG. 10.

FIG. 12 is a right end elevation of the tubular bearing shown in FIGS.10 and 11.

FIG. 13 is a top plan view of the tubular bearing shown in FIGS. 10-12.

FIG. 14 is a left end elevation of the second form of the improvedtubular bearing.

FIG. 15 is a fragmentary longitudinal vertical sectional view thereof,taken generally on line 15-15 of FIG. 14.

FIG. 16 is a right end elevation of the tubular bearing shown in FIG.15.

FIG. 17 is a top plan view of the tubular bearing shown in FIGS. 14-16.

FIG. 18 is a left end elevation of a third form of the improved tubularbearing.

FIG. 19 is a fragmentary longitudinal vertical sectional view thereof,taken generally on line 19-19 of FIG. 18.

FIG. 20 is a right end elevation of the tubular bearing shown in FIG.19.

FIG. 21 is a top plan view of the tubular bearing shown in FIG. 19.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

At the outset, it should be clearly understood that like referencenumerals are intended to identify the same structural elements, portionsor surfaces consistently throughout the several drawing figures, as suchelements, portions or surfaces may be further described or explained bythe entire written specification, of which this detailed description isan integral part. Unless otherwise indicated, the drawings are intendedto be read (e.g., cross-hatching, arrangement of parts, proportion,degree, etc.) together with the specification, and are to be considereda portion of the entire written description of this invention. As usedin the following description, the terms “horizontal”, “vertical”,“left”, “right”, “up” and “down”, as well as adjectival and adverbialderivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”,etc.), simply refer to the orientation of the illustrated structure asthe particular drawing figure faces the reader. Similarly, the terms“inwardly” and “outwardly” generally refer to the orientation of asurface relative to its axis of elongation, or axis of rotation, asappropriate.

Referring now to the drawings, and, more particularly, to FIGS. 1-6thereof, the present invention broadly provides an improved bearingassembly that permits machine tool spindles to be quickly exchangedwhile obviating the need to recenter a replacement spindle with respectto a body opening after the original spindle has been initially centeredtherein.

A first form of the improved bearing assembly is generally indicated at25 in FIGS. 1 and 2; a second form is generally indicated at 26 in FIGS.3 and 4; and a third form is generally indicated at 28 in FIGS. 5-6. Ineach case, the bearing assembly includes a tubular sleeve, generallyindicated at 29, formed of a ferrous metal and mounted in an opening 30of a body 31. As best shown in FIGS. 1, 3 and 5, the body opening 30includes an inwardly-and leftwardly-facing frusto-conical surface.Moreover, a blind hole 32 extends radially into the body from opening 30to accommodate and receive one marginal end portion of a pin 33.

As best shown in FIGS. 7-9, the tubular sleeve 29 is ahorizontally-elongated specially-configured tubular member having anannular vertical left end face 34, an annular vertical right end face35, a stepped inner surface that sequentially includes aninwardly-facing horizontal cylindrical surface 36 extending rightwardlyfrom left end face 34, a rightwardly-facing annular verticalshoulder-38, and an inwardly-facing horizontal cylindrical surface 39continuing rightwardly therefrom to join right end face 35. The tubularsleeve is also shown as including an outer surface that includes (inpertinent part): an outwardly-and rightwardly-facing frusto-conicalsurface 40 extending rightwardly from the outer margin of left end face34, and an externally-threaded portion 41 adjacent right end face 35. Ablind hole 42 extends radially into the tubular sleeve to accommodateand receive the inner marginal end portion of pin 33. This pin is usedto prevent relative movement, both axially and rotationally, of thetubular sleeve 29 relative to body 31.

Still referring to FIG. 8, a diametrical through-hole, indicated at 43,extends through an intermediate portion of the tubular sleeve. Anannular groove, indicated at 44, extends into the tubular sleeve fromits outer surface, and separates frusto-conical portion 40 fromexternally-threaded portion 41. The tubular sleeve is shown as havingtwo diametrically-opposite tongues, severally indicated at 45, thatextend axially beyond right end face 35. These two tongues 45, 45constitute locating tabs, that are adapted to engage adjacent structure.

Adverting now to FIGS. 1 and 2, the first form of the improved bearingassembly is shown as including a tubular bearing, generally indicated at46, arranged within sleeve 29.

As best shown in FIGS. 10-13, bearing 46 is shown as being ahorizontally-elongated tubular member having an annular vertical leftend face 48, an annular vertical right end face 49, an inwardly-facinghorizontal cylindrical surface 50, and a stepped outer surface thatsequentially includes: an outwardly-facing horizontal cylindricalsurface 51 extending rightwardly from the outer margin of left end face48, a shallow annular groove 52, a flange portion 53 extending outwardlybeyond surface 51, and an outwardly-facing horizontal cylindricalsurface 54 continuing rightwardly therefrom to join the outer margin ofright end face 49. Flange 53 is defined by a leftwardly-facing annularvertical surface 55 extending outwardly from surface 51, anoutwardly-facing horizontal cylindrical surface 56, and arightwardly-facing annular vertical surface 58 extending inwardlytherefrom and joining the left marginal end portion of surface 54.

A shallow annular groove, indicated at 59, extends into bearing 46 froman intermediate portion of inner surface 50, and is intersected by adiametrical through-hole 60. A tapped blind hole 61 extends horizontallyinto bearing 46 from the 6:00 o'clock position of its left end face toaccommodate and receive a headed fastener, indicated at 62 in FIGS. 1and 2. Fastener 62 is adapted to be matingly received in hole 61, andthe head portion thereof is adapted to engage the left end face of theleft end face 34 of the tubular sleeve to limit relative axial movementtherebetween. As best shown in FIGS. 10 and 12, bearing flange 53 isprovided with two diametrically-opposite slots, severally indicated at63.

Adverting now to FIGS. 3 and 4, the second form 26 of the improvedbearing assembly is shown as including ferrous tubular sleeve 29, and analternative form of the tubular bearing, this form being generallyindicated at 65.

As best shown in FIGS. 14-17, bearing 65 is a horizontally-elongatedspecially-configured tubular member having an annular vertical left endface 66, an annular vertical right end face 68, and an inwardly-facinghorizontal cylindrical surface 69 extending therebetween. A shallowcircumferential groove 70 extends radially into the bearing from anintermediate position of inner surface 69. A longitudinally-extendinggroove 71 extends radially into bearing 65, and intersectscircumferential groove 70. Grooves 70 and 71 providecircumferentially-and axially-extending lubricant distribution grooves.

Here again, a tapped line hole 72 extends into bearing 65 from the 6:00o'clock position of its left end face to accommodate and receive aheaded fastener 73, which engages the left marginal end portion of thetubular sleeve to limit relative axial movement therebetween in onedirection.

Bearing 65 is also shown as having an outer surface that sequentiallyincludes an outwardly-facing horizontal cylindrical surface 74 extendingrightwardly from the outer margin of left end face 66, aleftwardly-facing annular vertical surface 75, and a horizontalcylindrical surface 76 continuing rightwardly therefrom to join theouter margin of right end face 68. A shallow annular filleted groove 78is provided between surfaces 74 and 75. A pair of diametrically-oppositeinclined ramps, generally indicated at 79, extend rightwardly andslightly inwardly from surface 74, and join right end face 68.

Adverting now to FIGS. 5 and 6, the third form 28 of the improvedbearing assembly is shown as including tubular sleeve 29 and athin-walled tubular bearing, generally indicated at 80.

As best shown in FIG. 21, bearing 80 is a specially-configuredhorizontally-elongated member having an annular vertical left end face81, a annular vertical right end face 82, and an inner cylindricalsurface 83 extending therebetween. A plurality of helical grooves,portions of which are indicated at 84, extend into bearing 80 from itsinner surface 83 to distribute lubricant therealong. Bearing 80 is shownas having an outer surface that includes, in pertinent part: ahorizontal cylindrical surface 85 extending rightwardly from the outermargin of left end face 81, an leftwardly-facing annular verticalsurface 86, and an outwardly-facing horizontal cylindrical surface 88continuing rightwardly therefrom to join the outer margin of right endface 82. A diametrical hole 89 extends through an intermediate portionof bearing 80 and intersects lubricant-distributing spiral groove 84. Afilleted annular groove 90 extends radially into bearing 80 betweenouter surfaces 85 and 86. A pair of inclined-diametrically-oppositeflats, severally indicated at 91, extend rightwardly from surface 85.

All three forms of the improved bearing assembly use common tubularsleeve 29. However, the individual bearing assemblies differ in that thetubular bearing member differs for each bearing assembly. In each case,the tubular bearing is formed of bronze. In each case, after the bearingassembly has been initially mounted on the body, the bearing assemblymay be disassembled, by unthreading nut 92, to allow the bearingassembly to be disassembled in situ. In other words, the outer tubularsleeve would remain mounted on the body in a centered position withrespect to the body opening. Hence, the outer sleeve need only beinitially shimmed to center its axis with respect to that of theopening. Thereafter, screws 62 (FIGS. 1-2), 73 (FIGS. 3-4), or retainingring 93 (FIGS. 5-6) may be selectively removed to allow the bearingassembly to be disassembled by removing the tubular bearing from withinthe tubular sleeve. This will allow the spindle to be removed.

In FIGS. 1, 3 and 5, three different spindles indicated at S1, S2 andS3, respectively are depicted. A replacement spindle, whether theoriginal spindle or another, may then be reinserted, and the bearingassembly reassembled without having to recenter the outer sleeve withrespect to the body opening. Thus, the improved bearing assembly allowsspindles to be quickly exchanged, while obviating the need to recenterthe replacement spindles.

Modifications

The present invention contemplates that many changes and modificationsmay be made. For example, the materials of construction are not deemedto be critical, unless expressed in the claims, and may be readilychanged or modified as desired. While it is presently preferred to usebronze as the material of the journal bearing, other types of journalbearing materials might possibly be used.

Therefore, while three preferred forms of the present invention havebeen shown and described, that several modifications thereof discussed,persons skilled in this art will readily appreciate that variousadditional changes and modifications may be made without departing fromthe spirit of the invention, as defined and differentiated by thefollowing claims.

1. In a machine tool having a spindle mounted in a body opening formovement relative to said body, the improvement comprising: a bearingassembly that permits spindles to be quickly exchanged while obviatingthe need to recenter a replacement spindle with respect to said openingafter the original spindle has been initially centered therein, saidbearing assembly including: a tubular sleeve of a ferrous metal mountedin said body opening, said sleeve having an outer surface arranged toface toward the portion of said body that surrounds said opening andhaving an inner surface arranged to face toward a penetrant portion of aspindle; and a tubular bearing arranged within said sleeve, said tubularbearing having an outer surface arranged to face said sleeve innersurface and having an inner surface arranged to face said spindlepenetrant portion.
 2. The improvement as set forth in claim 1 whereinsaid tubular bearing inner surface is arranged to slidably engage saidspindle penetrant portion.
 3. The improvement as set forth in claim 2wherein said sleeve inner surface is cylindrical.
 4. The improvement asset forth in claim 1 wherein a portion of said sleeve outer surface isfrusto-conical.
 5. The improvement as set forth in claim 1 wherein saidtubular bearing is formed of bronze.
 6. The improvement as set forth inclaim 5 wherein said spindle is mounted in said body opening forrotational and axial movement relative to said body.
 7. The improvementas set forth in claim 1, and further comprising: a pin engaging saidbody and said tubular sleeve to prevent relative movement therebetween.8. The improvement as set forth in claim 7 wherein said body is providedwith a blind hole to receive one marginal end portion of said pin. 9.The improvement as set forth in claim 8 wherein said tubular sleeve isprovided with a blind hole to receive the opposite marginal end portionof said pin.
 10. The improvement as set forth in claim 1 wherein agroove extends into said tubular bearing from said inner surface thereoffor distributing lubricant between said spindle and said bearing innersurface.
 11. The improvement as set forth in claim 10 wherein saidgroove extends into said bearing in a longitudinal direction.
 12. Theimprovement as set forth in claim 10 wherein said groove extends intosaid bearing in a radial direction.
 13. The improvement as set forth inclaim 10 wherein said groove extends helically into said bearing. 14.The improvement as set forth in claim 1 wherein a portion of said sleeveouter surface is externally threaded, and further comprising: a nutarranged to matingly engage said sleeve externally-threaded portion. 15.The improvement as set forth in claim 1 and further comprising: ainterlock mechanism acting between said sleeve and bearing to preventrelative movement therebetween in one direction.
 16. The improvement asset forth in claim 15 wherein said interlock mechanism includes a tappedhole arranged in one of said sleeve and bearing, and a headed fastenerthreaded into said tapped hole and having a head portion engaging theother of said sleeve and bearing.
 17. The improvement as set forth inclaim 15 wherein said interlock mechanism includes an annular grooveextending into one of said sleeve and bearing, and a retaining ringhaving one portion received in said annular groove and having anotherportion engaging the other of said sleeve and bearing.